Nicole Scherzinger remained tight-lipped about her X Factor return as she attended an anti-human trafficking event in Los Angeles.

There are doubts over whether the former Pussycat Doll would reprise her role as a judge on the ITV show for the next series, along with Tulisa Contostavlos. Gary Barlow and Louis Walsh are expected to return to the panel, while former judge Sharon Osbourne is reportedly on the verge of signing a deal to join the revamped show.

But Nicole said: "I don't know yet. We'll just have to wait and see."

The singer, who was dressed in a white outfit from high street stores River Island and Zara, was helping to raise awareness about human slavery alongside Jada Pinkett Smith and her daughter Willow at the annual From Slavery To Freedom gala in Beverly Hills, organised by the Coalition to Abolish Slavery and Trafficking.

"It's crazy that it exists. Human trafficking is the modern-day slavery and it's bigger than ever. People don't realise it's the biggest trade, it's a nine million US dollar industry. It's the fastest growing criminal enterprise of the 21st century and it's happening in our back yards," she said.

"People don't understand. They sometimes think of prostitution, but it's actually young girls who are repeatedly raped and sold into sex slavery. Anybody who has a child and knows a child, you can't turn a blind eye to it. You have to fight back, you have to bring awareness so I'm here to bring a voice."